Waste heat boiler



July 21, 1936. G. wELTER 2,048,308

WASTE HEAT BOILER Filed Aug. 1, 1935 INVENTOR 6 0.9 7/? V6 W51 75/?TTORNEYS Patented July 21, 1936 OFFICE Gustave WelterfiNewHaven;Gonn;,"a signor to Thef-Bigelow-Company,New Haven,- Conn., a

corporation otzGonnecticutm; i

invention relatestoanlirnp veinentlin waste heat boilers. Ir'theirI'generalasp ctssuch' ile s w l kno e mbre em t ates t novel m ficti n of "the l KiIQ Il structure.- These modifications are" planned tobring about a new mode of boiler operation Q'particul ly in' thetransfer oflthe steam, fro H b H steam drum." One, adva "ta'ge s t titheconstruction avoids the ,breaking. do. joints betweenlthe tubes r d;the", p: Y sheet from which region the made steam scares the s a d mwillbe'explained in connection with the disclosure and description of theaccompanying drawing, in which Fig. 1 is a general view of a waste heatboiler with parts broken away to show the embodiment of the improvedstructure;

Fig. 2 is a diagrammatic view of steam connections between the boilerand the steam drum of Fig. 1 which are desirable to use in some cases,as will be pointed out; and

Fig. 3 is a side view on a reduced scale of the boiler, the steam andwater drum at the top ends and the manner of connecting an additionalcross connection. 7

The known details of this boiler are shown only generally. Gas, say froma gas plant, enters at the top opening I and leaves at the bottomopening 2. Fire tubes 3 are connected between upper and lower tubesheets 4 and 5 and are surrounded with water. The general circulationthrough the boiler is indicated by the arrows. The water to be addedenters at I at the top of pipe I. The latter has a cross connection 8 tothe boiler, just above the bottom tube sheet. A suitable water level forthe water and steam drum 6 is indicated at line a-a. The top connectionbetween the boiler and steam drum, as shown in the drawing, will beexplained later. It is to this top connection I l and its environmentthat my invention is particularly directed.

In prior art boilers of this kind the connection between the water andsteam drum has been made by a horizontally arranged nozzle, the top ofwhich has been in line with inside (lower) face of the top tube sheet.In such constructions, as the boiler makes steam, it collects under thistube sheet. It presses the water down in the boiler and finally escapesthrough the nozzle on the level of the tube sheet in passing to thedrum. As the water is pressed down in the boiler, it uncovers the tubesheet on its lower face. That is, this face is in contact with steamrather than water. In such prior art mode of operation the Ase rialhasten toptube sheet, receiving the full blast of hot gas fromthe inlet.pipe on its upper surface, is not sufiiciently coolediby the steam onits lower surface. The consequence is'that' the top sheetor platebe'cpmesoverheated to suchan extent that it is, slightly warped due toexpansion. br'eaks the tube joints enough to leak steam; aftertlieleaking starts it gets 'worse and worse by erosive action. Steam willnot keep the Plate 99 en a in- My invention is particularly directed toremedy defect in the prior art operation to do so Parti u a y "e eie w vIn ddi i n to avoiding'the defect mentioned, my arrangement has otheradvantages, as I will point out.

I provide an annular chamber l0 around the boiler, as shown. I connectthis space with the water and steam drum by nozzle H. As shown, thisnozzle has its opening overlapping the upper tube plate. The generalidea is to have the nozzle passage extend above the tube plate and inconnection with the annular chamber 10 above the tube plate.

As a constructional feature to cooperate with my plan of operation, tobe described, I preferably make the top plate A slightly convex on theunder side. A crown extending downwardly with a difference of one-halfinch between sides and center, for example, will avoid the possiblity ofany steam pocket forming on the under side of this head.

In this arrangement, as the boiler makes steam, it rises to the topplate 4 but it cannot collect there until under sufficient pressure topress the water down and thus escape to the drum. Instead of the priorart operation, the new arrangement requires the steam to pass, as fastas it is made, to the annular chamber Ill. This keeps water against theunder side of the tube plate and water acts enough better than steam incooling the tube plate 4 that the tube joints will not spring a leak inthe highly objectionable way and for the reason that they have beendoing in the past.

In the construction shown and described stea passes from the convexunder side of sheet 4 into chamber Hi. It cannot collect on the underside of the sheet 4 but must move to chamber Ill. The sides of theupperheader member are lined with refractory to avoid the steel at this pointbeing overheated. It would be preferable to make the top of passage lllevel with the very top of annular space It]. But there areconstructional objections to this in boiler work. So as shown I havemade the passage l I substantially up to the top of space I and providedan air vent II for the very top of said space. The boiler constructionindicated in Fig. 1 results in the walls of the annular space l0extending out 5 from what is ordinarily considered the shell and thenextending into what is ordinarily called the I header member so that theannular space Ill overlaps'the two. So by the term shell I refer in theclaims ,to both the tube and header sections of the boiler.

In Fig. 2 I have indicated additional connec-f said cross connectionbeing arranged to enter at tions between the anular space H] and thewater and steam drum. The two side ones li'and l6 are made in the samemanner and at the same level as the middle one I I. With thisarrangement the annular chamber l0 may empty its steam into the drumfaster than with a single connection. It makes for a better access 'fromboiler space to steam drum when more'than one connection ,is used.. Thetwo shown in addition torconnection ll give a well balanced arrangementbut more or less could be used.

As will be seen in Fig. 1, by my arrangement the upper head of theboiler adjacent upper tube plate 4 is kept submerged in the water of theboilerin a particular way to keep the head cool enough to avoidoverheating and consequent warping, and to transfer the steam to thedrum without trouble. 3O v. Having disclosed my improved boilerconstruction, I claim:

1'.' A, boiler comprising a shell having therein upperand lower tubesheets, tubes connecting said sheets, said shell having an entrance gaschamber above the top sheet and an exit gas chamber below the bottomsheet, an annular chamber around the shell extending from a level belowthe upper tube sheet to a level slightly 5 above said sheet and in freecommunication with the interior of said shell. and a water and steamdrumadjacent the top of the shell, a cross connection between saidannular chamber and said water and steam drum, said cross-connection en-10 tering said steam drum at the side of the latter,

' tube sheet and'adown flow connection from the 15 bottom. of-said drumto the lower portion of the water spacebetween said tube sheets, all forthe purpose described.

2.'.The structure of claim 1 in combination with an additional crossconnection between the. annular space and the steam and water drum. 3.The structure of claim 1 in combination with an air vent at the very topof the annular space above the cross connection to the steam andwaterdrum. 25

4. The structure of claim 1 in combination with" an additional crossconnection between the annular space and thesteam and water drum, saidadditional cross connection being smaller andjlocated at a higher levelthan the main cross connection.

GUSTAVE WELTER.

